Process for dyeing rayon knit piece goods



ug- 6, 1935. G. PUTNAM Er AL y2,010,320

PROCESS FOR DYEING RAYON KNIT PIECE GOODS Filed Jan. 12, 1929 nuewcou Patented Aug. 6, 1935 UNlTE-D STATES PATENT OFFICE PROCESS FOR DYEING RAYON KNIT PIECE GOODS George Ives Putnam and Clifford Tasker Wortlien, Utica, N. Y., assignors to McLoughlin Textile Corporation, Utica, N. Y., a corporation of New York Application January 12, 1929, serial No. 332,074

18 Claims.

ing of rayon is enhanced.

An object of the invention is to provide a process by which rayon may be dyed fast shades with the various classes of vat dyes so that the colors will not be affected by the usual agencies as light, washing, etc.

Another object of the invention is to provide a process for dyeing rayon in the form o knit piece goods a variety of shades with vat dyes.

A further object of the invention is to provide a process whereby rayon knit'piece goods may be dyed fast shades commercially in an economical manner in large quantities in a dyeing machine.

Furthermore itis an object of the invention to provide a process for dyeing rayon knit piece goods with vat dyes giving fast to light and Washing shades with not only a retainment of the inherent qualities of the rayon, but with an enhancement of their desirable properties.

Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the several steps and the relation and order of one or more such steps with respect to each of the others, and the apparatus embodying features of construction combinations of elements and arrangement of parts which are adapted to effect such steps, allas exemplified in the following detailed disclosure, andthe scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had tothe following detailed description taken in connection with the accompanying drawing, in which the figure represents a side elevation, partly broken away, of a dyeing machine suitable for carrying out the dyeing operation. This machine consists of the usual tub I, which is provided with a perforated partition 2 for maintaining the knit piece goods 3 out of direct contact with the wall of the tub and so curved as to render the reeling or working of the goods easy. The sides and ends of the tub are provided with suitable outlets 4 for the overow of the liquid during the washing operation. Positioned above the tub are driving gears 6 and 1, a carrying roll 3, a large reel 9 and a small reel I0. The roll 8 is an idling roll. The reels 9 and I0 are driven by a chain It and a belt I2, respectively. The reel l0 is much smaller than the reel 9.

In the dyeing operation the goods is worked over the large reel previous to the introduction of the vat dye, and is removed from the large reel and passed over the small reel I0 just before introducing the dyestui or coloring material. ,The drive of the small reel is such that it travels at a rate which is about 10% faster than that of the large reel, and being of small diameter, the goods is reeled'through the liquor in the tub more rapidly whereby the time of exposure to the air is materially lessened. The tub is also provided with a pipe not shown in the drawing by means of which wash Water is introduced when the dyeing operation has been completed.

In the practice of the invention the dyeing machine is filled to the. proper level with water to which an alkali and a retarding agent are added. Into this bath the rayon knit piece goods is introduced and worked therethrough in the cold until the goods is thoroughly saturated with the bath liquor. This is desirable in order to obtain level shades. When the goods is saturated, which may require a period of about twenty minutes, a reducing agent is added, and when well distributed throughout the bath, the vat dyestuff for the shade desired is added in the reduced condition, i. e., 'the dyestuff has been suitably reduced before introduction into the bath containing a reducing agent in order that the reduced condition may be maintained.

The working or reeling of the goods through the bath is continued with increase of temperature until the dyestuff is fixed by the ber. The increase in temperature is gradual and reaches at least 100 degrees F., whereupon it is maintained throughout the dyeing operation. The dyeing having been completed, wash water is introduced with reeling of the goods being continued until the dyeing solution is removed from the fiber. It is not desirable to dump the dye bath and then to Wash, but rather it has been found more satisfactory to introduce the wash water into the bath in the form of a spray and allow the liquid to run off through the overflows provided therefor about the tub. When the washing is completed, the dyestuff is oxidized by running in a bath containing 'an oxidizing agent such as hydrogen peroxide, sodium perborate or other suitable oxidizing agent, and is finished by a Soaping in hot solution. The goods is then dried, whereupon i't is ready for manufacture into various garments or other articles.

There are various methods by which rayon is manufactured. Those mostly used are the viscose, the copper ammonia, the nitrocellulose and the cellulose acetate. 'I'he rst three methods the case of the viscose, copper ammonia and nitrocellulose rayon, an alkali, as caustic soda,

lwill have, in addition to the eiect during the dyeing operation, a beneficial action upon the structure of the rayon, which gives to the nished material, a special soft, velvety, silk-like feel and finish. When dyeing a cellulose acetate rayon, in order to retain the characteristic properties of this type of rayon, attention should be given to the fact that inasmuch as cellulose acetate is an ester, it is therefore capable of saponication by an alkali, and care is to be exercised so that the amount of alkali used in the dye bath is not suicient to materially affect or saponify the cellulose acetate. Should this care not be exercised, the rayon produced will have the characteristics rather of the viscose type than of the cellulose acetate type.

The vat dyes or coloring matters, which are used in a, reduced condition, are those belonging to the indigoid, carbazol and anthraquinone classes.

'I'he method of procedure in general is that a bath is prepared in the tub of the dyeing machine containing an alkali, such as caustic soda, or caustic potash, and a retarding agent which may be a sulphite Waste liquor product or derivative. The rayon knit piece goods are run in this bath for a period suiicient to thoroughly saturate the goods, in order to insure level dyeing. This preliminary treatment with the retarding agent is of importance in preventing the dye-stuff when added from going into the cloth to rapidly with the result that the dye-stuff would tend to deposit itself unevenly upon the cloth due to its too rapid exhaustion. The preliminary treatment of the goods with the retarding agent thus acts to provide for particularly level dyeing. A period of twenty minutes has been found to give satisfactory results. To this bath is then added therequired amount of reducing agent as sodium hydrosulphite, and when this agent has been Well distributed throughout the bath, there is added the desired vat dyestuif previously reduced. The preparation of the dye solution may be made by dissolving the required quantity for the shade to be' produced in water containing sodium hydrosulphite and caustic soda or caustic potash. The contents are stirred until reduction is completed, whereupon it is ready for use in the dye bath. In dyeing the knit piece goods, the dye bath should at all times be in a reduced state. Otherwise imperfect and non-level shades willl result.

The dyeing operation is started in the cold, and

the goods, which has previously been reeled by passing over the roller 8'and the reel 9, is now passed over the roll 8 and the reel I 0 in order to reduce the time of exposure to air and thus to decrease the tendency to oxidation, and the temperature is gradually raised to that required for the particular dyeing operation. The reeling of the piece goods'is continued at this temperature, which may Vary f rom to 160 degrees F., depending upon the material and the dyestuif being used, until the desired shade is obtained.' The goods are then washed free of the bath liquor by a, spray of water entering beyond the perforated partition at the left of the dyeing machine and flowing out through the overflows at the sides and ends of the tub. The washing is continued until the dye liquor is thoroughly removed, whereupon the goods is oxidized by passage through a bath which may contain hydrogen peroxide as the oxidizing agent. The operation is completed by a soaping in hot solution, for example at a temperature of 180 degrees F. in order to fully develop the shade and to limpart fastness. 'I'he goods maythen be dried and utilized in the manner desired.

More in particular, but also a general formula, the dyeing of 400 pounds of rayon knit piece goods may be accomplished in a bath containing the vat dye in the percentage for the shade to which the work is directed: 900 to 1000 gallons of water;9 to 20 pounds .of caustic soda; 7 to 12 pounds of sodium hydrosulphite; and 1 to 4 pounds retarding agent, as a sulphite Waste liquor product. It has been found that within the limits here given, practically any shade may be obtained on rayon knit piece goods with vat dyes. It may be mentioned, however, that the quantities of caustic soda, sodium hydrosulphite and retarding agent will vary somewhat with the various dyes and the best results must be ascertained for each. Also the ability of the rayon to iix or take up the various vat colors varies, and the dyeing conditions are to be adjusted in order to obtain the best results with respect to this factor.

The examples hereinafter given present illustrative details of procedures adapted for use with particular dyes pursuant to the foregoing:

Example I Example II Rayon knit piece goods may be dyed a honeydew shade by using an orange carbazol vat dye in paste form in an amount of with the use of 10 pounds of caustic soda, 8 pounds of sodium hydrosulphite, 3 pounds of the sulphite waste liquor product, and 1000 gallons of water. Four hundred pounds of rayon knit piece goods are dyed in this bath, being entered cold and the temperature gradually raised to and maintained at 160 degrees F.

Example III Rayon knit piece goods may be dyed a nile green shade by the use of a mixture of anthraquinone vat dyes, for example, an anthraquinone green vat dye in paste form in Van amount of and an anthraquinone yellow vat dye in powder form }4% utilizing 1000 gallons of water, 20 pounds of caustic soda, 10 pounds of sodium hydrosulphite, and 3 pounds of the sulphite waste liquor product. 400 pounds of rayon piece goods are dyed. The temperature is gradually raised to and maintained at degrees F.

6. A process of dyeing, which comprises reeling Example IV Cellulose acetate rayon knit piece goods may be dyed a scarlet shade with a red indigoid vat dye in an amount of l/% utilizing '700 gallons of water, 7 pounds of caustic soda, 6 pounds of sodium hydrosulphite and 2 pounds of the sulphite waste liquor product. 200 pounds of cellulose acetate rayon are reeled, being entered cold, and the temperature gradually raised and maintained at 140 degrees F. When the dyeing is completed the washing, oxidizing and soaping is as previously described.

Vat dyes of the carbazol and anthraqunone classes may be used for the dyeing of cellulose acetate rayon. For example, if a violet shade is desired, it may be obtained by dyeing in a bath containing a violet carbazol vat dye powder, and if a blue shade, it may be developed in a bath containing a blue anthraqunone vat dye.

As exemplifying other vat dyes which may be used, more particularly with 'rayon of the viscose, copper ammonia and nitrocellulose types, mention may be made of carbazol and anthraquinone dyes.

It is to be understood that Asulphite waste liquor derivatives are included under the terms sulphite waste liquor product and sulphite waste liquor etc. as used herein. y

Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. A process of dyeing, which comprises working rayon knit piece goods in a bath containing an alkali and a retarding agent, subsequently adding a reducing agent and a vat dye in reduced condition, continuing the working until the dye has been iixed, and then washing and oxidizing.

2. A process of dyeing, which comprises working rayon knit piece goods in a bath containing an alkali and a retarding agent for about twenty minutes, subsequently adding a reducing agent and a vat dye in reduced condition, continuing the working until the dye has been fixed and then washing and oxidizing. u

3. A process of dyeing, which comprises working rayon knit piece goods in a bath, in the cold, containing an alkali and a retarding agent, subsequently adding a reducing agent and a vat dye in reduced condition, continuing the working with increase of temperature until the dye has been iixed, and then washing and oxidizing.

4. A `process of dyeing, which comprises working rayon knit piece goods in a bath, in the cold, containing an alkali and a retarding agent for aboutvtwenty minutes, subsequently adding a reducing agent and a vat dye in reduced condition, continuing the working with increase of temperature until the dye has been iixed, and then washing and oxidizing.

5. A process of dyeing, which ,comprises working rayon knit piece goods in a bath, in the cold, containing an alkali and a retarding agent for about twenty minutes, subsequently adding a reducing agent anda vat dye in reduced condition, continuing the working with increase 'of temperature until the dye has been fixed, then washand oxidizing, and Soaping ina hot solution.

rayon knit piece goods through a bath, in the cold, containing a caustic alkali and a sulphite waste liquor product as a retarding agent for about twenty minutes, subsequently adding sodium hydrosulphite and a vat dye in reduced condition, continuing the reeling with increase of temperature until the dye has been fixed, and finally washing, oxidizing and soaping in hot solution.

7. A process of dyeing, which comprises working rayon fabric for a period of time in `a bath containing an alkali compound and a retarding agent, and thereafter including in said bath a vat dye and a reducing agent, and continuing the working.

8. A process of dyeing, which comprises working rayon fabric for a period of time in a bath containing an alkali compound and a retarding agent, and thereafter including in said bath a vat dye in reduced condition and a reducing agent, and continuing the working.

9. A process of dyeing, which comprises working rayon fabric for a period of time in a bath containing an alkali compound and a retarding agent, and thereafter including in said bath a vat dye and a reducing agent, and continuing the working, the retarding agent being in the proportion of .01 to .04 pound to each 9 to 10 gallons of water.

10. A process of dyeing, which comprises working rayon fabric for a period of time suilicient to thoroughly saturate the goods in a bath containing an alkali and a retarding agent, and thereafter including in said bath a vat dye and a reducing agent, and continuing the working.

1l. A process of dyeing, which comprises workingrayon fabric for a period of time suicient to thoroughly saturate the goods in a bath containing an alkali and a retarding agent, and thereafter including in said bath a vat dye and a reducing agent, and continuing the working with increase in temperature.

12. A process of dyeing, which comprises working rayon goods in a bath containing an alkali and a retarding agent, subsequently distributing a reducing agent throughout said bath and thereafter adding a vat dye in reduced condition and continuing theworking until the dye has been fixed, and then washing and oxidizing.

13. A process of dyeing, which comprises worlring rayon goods in a bath containing an alkah and sulphite waste liquor, subsequently dis- A tributing a reducing agent throughout said bath and thereafter adding a vat dye in-reducedcondition and continuing and working until the dye has been fixed, and then washing and oxidizing.'

14. A process of dyeing, which comprises working piece goods in a bath containing an alkali and a retarding agent, and subsequently including in the bath a reducing agent and a vat dye in reduced condition. g

15. A process of dyeing, which comprises working piece goods in a bath containing an alkali and a sulphite waste liquor product, and subsequently adding a reducing agentand a vat dye in re*- duced condition.

16. A process of dyeing, which comprises working piece goods in a bath containing an alkali and a sulphite waste liquor product, subsequently adding a reducing agent and a vatdye in reduced condition, continuing the working with an increase in temperature until the dye has been fixed, and then washing and oxidizing.

17. A process of dyeing, which comprises work- CII ing piece goods in a bath containing an alkali and a sulphite waste liquor product for about twenty minutes, subsequently adding a vat dye in reduced condition, continuing the working in the presence of a reducing agent with an increase of temperature until the dye has been fixed, and then Washing and oxidizing.

18. A process of dyeing, which comprises working piece goods in a bath containing an alkali and a retarding agent, and subsequently including in the bath a reducing agent and a vat dye in reduced condition, and which involves utilizing the ingredients in the following proportions with respect to each nine or ten gallons of water: sulphite waste liquor product .01 to .04 pound, caustic soda about .09 to .2 pound, sodium hydrosulphite about .07 to .12 pound, and a vat dye in suitable proportion.

GEORGE IVES PUTNAM.

CLIFFORD TASKER WORTHEN. 10 

